The Prince of Wales has become president of the UK arm of the WWF. Photograph: Wpa Pool/Getty Images

The Prince of Wales made an impassioned plea for humanity to safeguard the natural world for future generations as he became president of WWF-UK.

Against the background of global threats such as climate change, rainforest destruction and dwindling fish stocks, Charles said on Thursday that he was taking up the reins of the conservation charity at a "crucial moment".

In a speech at St James's Palace to mark his new role with the WWF's (World Wildlife Fund) UK arm, the prince suggested that a new "cause celebre", like the WWF's famous fight to safeguard the panda, was needed to highlight the predicament the world was facing.

Charles said the receding Arctic sea ice cap might be the issue that prompts the world to think about what people are doing to the planet. Speaking to WWF-UK staff and other environmentalists the prince said that what was needed was "robust leadership into the future".

He added: "For history will not judge us by how much economic growth we achieve in the immediate years ahead, nor by how much we expand material consumption, but by the legacy we leave for our children, grandchildren and their grandchildren.

"We are consuming what is rightfully theirs by sacrificing long-term progress on the altar of immediate satisfaction and convenience. That is hardly responsible behaviour.

"There is an urgent need for all of us to concentrate our efforts on sustaining, nurturing and protecting the earth's natural capital and, moreover, reshaping our economic systems so that nature sits at the very heart of our thinking.

"This is the mission of WWF-UK, and it is my mission as well."

The heir to the throne's green credentials are well known as he has campaigned on a range of environmental issues for many decades focusing on concerns such as protecting the world's rainforests and promoting sustainability.

Charles also countered the "criticism" he has faced over the years saying he put up with it as the issues were so important, adding "none of us must be afraid to stand up and be counted".

The royal takes over the presidency from his cousin, Princess Alexandra, the Honourable Lady Ogilvy, and also follows in the footsteps of his father, the Duke of Edinburgh, who was the first president of WWF-UK and now holds the position of president emeritus of WWF.